public MeshNode ConstructMeshTree()
{
// Create the grid
CreateGrid();
// Do the hierarchical clustering on the grid
Dictionary <Vector3, MeshNode> slotClusterAssign = new Dictionary <Vector3, MeshNode>();
int maxClusterSize = 1;
// Assign the slotClusterAssign
foreach (Vector3 key in slots.Keys)
{
slotClusterAssign.Add(key, new MeshNode(slots[key].GetMesh(), key, slots[key].GetOffset()));
}
// Processing queue
Queue <List <Vector3> > clusters = new Queue <List <Vector3> >();
// Add initial clusters to the queue
System.Random rand = new System.Random();
List <Vector3> randomOrder = new List <Vector3>(slotClusterAssign.Keys);
randomOrder.Sort((x, y) => rand.Next(100000));
foreach (Vector3 key in randomOrder)
{
List <Vector3> cluster = new List <Vector3>();
cluster.Add(key);
clusters.Enqueue(cluster);
}
while (maxClusterSize != slots.Count && clusters.Count != 0)
{
// Get the processing position
foreach (Vector3 procPos in clusters.Dequeue())
{
// Get the node behind the key
MeshNode procNode = slotClusterAssign[procPos];
// Get all the positions inside the cluster (this nodes cluster)
HashSet <Vector3> selfClusterPositions = new HashSet <Vector3>(procNode.GetPositions());
// Find the neighboring cluster with the lowest size
int minClusterSize = 1000;
Vector3 minClusterKey = new Vector3(10000f, 10000f, 10000f);
foreach (Vector3 n in basisvectors)
{
// Get a neighbor key
Vector3 candidate = procPos + n;;
// Check if the candidate exists
if (!slots.ContainsKey(candidate))
{
continue;
}
// Check if the candidate is in the same cluster as current node
if (selfClusterPositions.Contains(candidate))
{
continue;
}
// Check the size of the cluster
MeshNode neigh = slotClusterAssign[candidate];
if (neigh.GetSize() < minClusterSize)
{
minClusterSize = neigh.GetSize();
minClusterKey = candidate;
}
}
// No eligable neighbours
if (minClusterSize == 1000)
{
continue;
}
// Now we know the cluster we want to pair with
// Get the node of the cluster
MeshNode clusterNode = slotClusterAssign[minClusterKey];
// Create a new cluster where the children are the current cluster and the neighbor cluster
MeshNode newNode = new MeshNode(clusterNode.GetMesh(), procNode.GetMesh());
newNode.AddChild(clusterNode);
newNode.AddChild(procNode);
// Get all the positions in the new cluster
List <Vector3> clusterPositions = newNode.GetPositions();
// Update the cluster assignment
foreach (Vector3 position in clusterPositions)
{
slotClusterAssign[position] = newNode;
}
// Add the cluster positions to the processing queue
clusters.Enqueue(clusterPositions);
// Get the cluster size
if (newNode.GetSize() > maxClusterSize)
{
maxClusterSize = newNode.GetSize();
// Early exit if task is already finished
if (maxClusterSize == slots.Count)
{
break;
}
}
}
}
// Return the topmost cluster
return(slotClusterAssign[new Vector3(0f, 0f, 0f)]);
}